Image forming apparatuses are used as printers, facsimile machines, copiers, plotters, or multi-functional devices having two or more of the foregoing capabilities. As one type of image forming apparatus employing a liquid-ejection recording method, an inkjet recording apparatus is known that uses a recording head (liquid-droplet ejection head) for ejecting droplets of ink. During image formation, such liquid-ejection-type image forming apparatuses eject droplets of ink or other liquid from the recording head onto a recording medium to form a desired image.
Such liquid-ejection-type image forming apparatuses fall into two main types: a serial-type image forming apparatus that forms an image by ejecting droplets from the recording head while moving the recording head in a main scanning direction of the carriage, and a line-head-type image forming apparatus that forms an image by ejecting droplets from a linear-shaped recording head held stationary in the image forming apparatus.
Such a liquid-ejection-type image forming apparatus may have image failures, such as “feathering” in which dots formed with liquid droplets blur in an jaggy shape on the recording medium and “color bleeding” in which, e.g., ink droplets of different colors mix each other at adjacent areas on the recording medium to blur color boundaries. Alternatively, such a liquid-ejection-type image forming apparatus may take a relatively long time to dry liquid droplets on a recording medium after image formation.
To cope with such failures, a pretreatment liquid may be applied by an application roller onto the recording medium before image formation so as to react ink on the recording medium to minimize bleeding. Alternatively, a pretreatment liquid may be ejected from the liquid ejection head in mist form onto the recording medium. Moreover, a treatment liquid may be applied in foam onto the recording medium.
As described above, in a case in which such a treatment liquid is applied to the recording medium, typically, a portion of a squeeze roller is immersed in the treatment liquid stored in a pan, and the squeeze roller draws up the treatment liquid to supply the treatment liquid to the application roller.
For such a configuration, however, while operation of the application device is stopped, moisture evaporates from the treatment liquid on the squeeze roller and the application roller. As a result, the treatment liquid dries and increases the viscosity, thus causing variance in the application amount of the treatment liquid when the application is resumed. To prevent such a failure, it is conceivable to initialize (restore) the condition of the treatment liquid on the application roller. However, such initialization may adversely increase the activation time in resuming the application of the treatment liquid.